﻿<?xml version="1.0" encoding="utf-8" ?>
<xsd:schema elementFormDefault="qualified" attributeFormDefault="unqualified"
            blockDefault="#all"
            xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://schemas.microsoft.com/windows/annotations/2003/11/core"
            xmlns:anc="http://schemas.microsoft.com/windows/annotations/2003/11/core">

  <!--  The Annotations element groups a number of annotations.  -->
  <xsd:element name="Annotations" type="anc:AnnotationsType" />

  <xsd:complexType name="AnnotationsType">
    <xsd:sequence>
      <xsd:element name="Annotation" minOccurs="0" maxOccurs="unbounded"
                   type="anc:AnnotationType" />
    </xsd:sequence>
  </xsd:complexType>

  <!-- AnnotationType defines the structure of the Annotation element. -->
  <xsd:complexType name="AnnotationType">
    <xsd:sequence>

      <!-- List of 0 or more authors. -->
      <xsd:element name="Authors" minOccurs="0" maxOccurs="1"
                   type="anc:AuthorListType" />

      <!-- List of 0 or more anchors. -->
      <xsd:element name="Anchors" minOccurs="0" maxOccurs="1"
                   type="anc:ResourceListType" />

      <!-- List of 0 or more cargos. -->
      <xsd:element name="Cargos" minOccurs="0" maxOccurs="1"
                   type="anc:ResourceListType" />

    </xsd:sequence>

    <!-- Unique annotation ID. -->
    <xsd:attribute name="Id" type="xsd:string" use="required" />

    <!-- Annotation "Type" is used to map the annotation to an annotation
         component that takes care of the visual representation of the
         annotation.  WPF V1 recognizes three annotation types:
  http://schemas.microsoft.com/windows/annotations/2003/11/base:Highlight
  http://schemas.microsoft.com/windows/annotations/2003/11/base:TextStickyNote
  http://schemas.microsoft.com/windows/annotations/2003/11/base:InkStickyNote
    -->
    <xsd:attribute name="Type" type="xsd:QName" use="required" />

    <!--  Time when the annotation was last modified.  -->
    <xsd:attribute name="LastModificationTime" use="optional"
                   type="xsd:dateTime" />

    <!--  Time when the annotation was created.  -->
    <xsd:attribute name="CreationTime" use="optional"
                   type="xsd:dateTime" />
  </xsd:complexType>

  <!-- "Authors" consists of 0 or more elements that represent an author. -->
  <xsd:complexType name="AuthorListType">
    <xsd:sequence minOccurs="0" maxOccurs="unbounded">
      <xsd:element ref="anc:Author" />
    </xsd:sequence>
  </xsd:complexType>

  <!-- The core schema allows any author type. Supported author types
       in version 1 (V1) are described in the base schema. -->
  <xsd:element name="Author" abstract="true" block="extension restriction"/>

  <!-- Both annotation anchor and annotation cargo are represented by the
       ResourceListType which contains 0 or more "Resource" elements. -->
  <xsd:complexType name="ResourceListType">
    <xsd:sequence>
      <xsd:element name="Resource" minOccurs="0" maxOccurs="unbounded"
                   type="anc:ResourceType" />
    </xsd:sequence>
  </xsd:complexType>

  <!-- Resource groups identification, location
       and/or content of some information.  -->
  <xsd:complexType name="ResourceType">
    <xsd:choice minOccurs="0" maxOccurs="unbounded" >
      <xsd:choice>
        <xsd:element name="ContentLocator" type="anc:ContentLocatorType" />
        <xsd:element name="ContentLocatorGroup" type="anc:ContentLocatorGroupType" />
      </xsd:choice>
      <xsd:element ref="anc:Content"/>
    </xsd:choice>

    <!-- Unique resource identifier. -->
    <xsd:attribute name="Id" type="xsd:string" use="required" />

    <!-- Optional resource name. -->
    <xsd:attribute name="Name" type="xsd:string" use="optional" />
  </xsd:complexType>

  <!-- ContentLocatorGroup contains a set of ContentLocators -->
  <xsd:complexType name="ContentLocatorGroupType">
    <xsd:sequence>
      <xsd:element name="ContentLocator" minOccurs="1" maxOccurs="unbounded"
                   type="anc:ContentLocatorType" />
    </xsd:sequence>
  </xsd:complexType>

  <!-- A ContentLocator describes the location or the identification
       of particular data within some context.  The ContentLocator consists
       of one or more ContentLocatorParts.  Each ContentLocatorPart needs to
       be successively applied to the context to arrive at the data.  What
       "applying", "context", and "data" mean is application dependent.
  -->
  <xsd:complexType name="ContentLocatorType">
    <xsd:sequence minOccurs="1" maxOccurs="unbounded">
      <xsd:element ref="anc:ContentLocatorPart" />
    </xsd:sequence>
  </xsd:complexType>

  <!-- A ContentLocatorPart is a set of "Item" elements.  Each "Item" element
       has "Name" and "Value" attributes that define a name/value pair.
       ContentLocatorPart is an abstract type that must be restricted for each
       concrete ContentLocatorPart definition.  This restriction should define
       allowed names and values for the concrete ContentLocatorPart type. That
       way the application can define its own way of locating information. The 
       ContentLocatorPartTypes that are allowed in version 1 (V1) of WPF are
       defined in the Annotations Base Schema.
  -->
  <xsd:element name="ContentLocatorPart" type="anc:ContentLocatorPartType"
               abstract="true" />

  <xsd:complexType name="ContentLocatorPartType" abstract="true"
                   block="restriction">
    <xsd:sequence minOccurs="0" maxOccurs="unbounded">
      <xsd:element name="Item" type="anc:ItemType" />
    </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="ItemType" abstract="true" >
    <xsd:attribute name="Name" type='xsd:string' use="required" />
    <xsd:attribute name="Value" type='xsd:string' use="optional" />
  </xsd:complexType>

  <!-- Content describes the underlying content of a resource.  This is an
       abstract type that should be redefined for each concrete content type
       through restriction.  Allowed content types in WPF version 1 are
       defined in the Annotations Base Schema.
  -->
  <xsd:element name="Content" abstract="true" block="extension restriction"/>

</xsd:schema>